Large screen displays have proven their worth for presenting information in an effective manner to groups of people or where the data content is such that its effectiveness is best appreciated by having a large amount of associated data available for viewing at the same time. The large screen displays can make useful information portrayals in a real-time scenario to educate and permit concerted, effective results.
Motion pictures and opaque projectors have demonstrated the validity of large screen displays and have allowed groups to gather in auditoriums and the like although the time taken for the development of films and opaque projector slides tends to compromise real-time viewing. Motion picture or opaque projectors are not suitable where real-time viewing or the available space restricts their use.
As a consequence, increased interest is shown in flat display technology which typically relies on a high resolution liquid crystal (LC) display panel with its associated thin film transistor (TFT), charge couple device (CCD) or laser addressing techniques.
The TFT-LCD is a known display element and is described in the article by Thomas L. Credelle entitled "GEs, LCs, TFT Panel" appearing in Public Information For A. M. Release. W., 7 Oct. 1987, From G. E. Research and Development Center, Schenectady, N. Y., #RDC 25,865-5-0.
Typically, a single LC display module forms an image in a liquid crystal layer sandwiched between a silicon integrated TFT circuit and a glass face plate. The TFT integrated circuit addresses the appropriate elements in the liquid crystal layer and a glass face plate couples the resulting image to a diffuser plane for viewing. Such is the arrangement shown in the "Liquid Crystal Fiber Optic Large Screen Display Panel" of Parviz Soltan et al. U.S. Pat. No. 4,299,447. The modulator unit changes its transmissivity in accordance with the appropriate signals so that a high intensity light emanating from a light source is channeled through the unit for an appropriate display.
Laser addressing of liquid crystal panels for a reflective large screen display is shown in a series of patents to John Trias et al. in his U.S. Pat. Nos. 4,533,215, 4,611,245 and 4,623,219. A single liquid crystal is depicted.
Costs and the complexity of merely making a larger single module can be prohibitive. There is a practical size limitation in the fabrication of a larger single module due to the inherent complexities of such an undertaking. Thousands of components are required in a TFT orientated module by only adding one inch in size, e. g. from a 8".times.8" module to a 9".times.9" module requires millions of dollars of capitol equipment investment plus the engineering complexities of solving shorts, component failure and associated malfunctions for the added size.
Because of the inherent complexities of fabrication associated with large LC/TFT display panels, their display capability is size limited to display modules which are relatively small. The size limitation for a large screen display might be overcome by abutting a number of these display modules in a mosaic pattern; however, a distracting, gap/grid line phenomenon is created. It is conceivable, by having the teachings of this invention in mind, that several of the above referred to display modules could have been used in a mosaic arrangement for an appropriate display, be it for direct reading or for viewing in a reflective mode of display.
The gap/grid line limitation is graphically portrayed in FIG. 1A in which a single LC/TFT display module with its X and Y scanners and drivers, is replicated and tiled together, as depicted in FIG. 1B. This mosaic approach creates unwanted gap/grid lines (G/GL) between the abutting LC modules which, at least, prove to be distracting to viewers.
Thus, a continuing need exists in the state of the art for a means for optically masking the unwanted gap/grid lines created between abutted adjacent display modules in a mosaic arrangement of display modules.